RPi Linux driver for Wolfson / Cirrus Logic Audio Card

I've been working on a reworked driver, based on Linux kernel 4.9, that doesn't require out-of-tree patches to the upstream kernel modules. This driver also adds a lot of new features and bugfixes like fixed micbias setting on LineIn, exposing of WM8804 status and AES bits as ALSA controls and configurable minimum/maximum samplerate limits.


The driver is included in official RPi kernels, you can install it with

sudo rpi-update

Source code is available from the usual place https://github.com/raspberrypi/linux.

Please note: If you've been compiling from source please switch to the official RPi kernel source. I'm no longer maintaining the code in my development tree cirrus-ng-4.9.y

Configuration for kernel 4.9

Enable the driver

Add the following line to /boot/config.txt to enable the Cirrus Logic card driver


Note: MMAP support is already enabled by default in kernel 4.9, you no longer need to add the i2s-mmap overlay.

Setup module dependencies

The cirrus driver requires some manually defined module dependencies, if you fail to add them the driver won't load properly.

Create a file /etc/modprobe.d/cirrus.conf with the following content:

softdep arizona-spi pre: arizona-ldo1

Download and install "usecase" mixer scripts

Download cirrus-ng-scripts.tgz and extract it for example in /home/pi/bin.

wget http://www.horus.com/~hias/tmp/cirrus/cirrus-ng-scripts.tgz
mkdir bin
cd bin
tar zxf ../cirrus-ng-scripts.tgz

Note: If you had installed the older usecase scripts for kernel 4.4 you need to remove them.

You have to start the appropriate scripts before you can use the card. For example:


Additional configuration steps

Disable RPi on-board audio device snd-bcm2835

On Raspbian the RPi on-board audio device snd-bcm2835 is enabled by default. When you run aplay -l you'll see two cards, the Cirrus card sndrpiwsp and the on-board card bcm2835.

If you don't need on-board audio you can disable it by removing (or commenting out) the dtparam=audio=on line from /boot/config.txt.


Optionally: use fixed card number

If you don't want to disable snd-bcm2835 or if you also have an USB audio device connected you might notice that the card numbers under which the drivers register will change. Sometimes the Cirrus card will card 0, sometimes on-board audio. The card number depends on which driver is registered first, which is purely random.

You can manually assign fixed card (slot/index) numbers using the slot option of the snd module. For example, if you want the Cirrus card always to be the first and on-board audio the second one, add the following line to your /etc/modprobe.d/cirrus.conf file:

For kernel 4.9 add this line:

options snd slots=snd-soc-rpi-cirrus,snd-bcm2835


If something doesn't work as expected please post your questions in this thread on the element14 site.

In order to track down problems follow the steps below and include the URLs to the paste files in your post:

  1. Add the following line to /boot/config.txt to enable devicetree debugging, then reboot your RPi.

  2. Upload your /boot/config.txt file, the GPU firmware version, GPU firmware and linux kernel logs and the outputs of lsmod and aplay -l. The easiest way to do this is by using the paste command which is included in Raspbian. Enter the following commands and include the URLs that are output on the terminal in your post:

    paste /boot/config.txt
    vcgencmd version | paste
    sudo vcdbg log msg 2>&1 | paste
    dmesg | paste
    lsmod | paste
    aplay -l | paste